package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.config.RedissionConfig;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.Voucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private RedissonClient redissonClient;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    @PostConstruct
    public void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取消息队列中的订单信息 XREAD GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );

                    //2.判断消息获取是否成功
                    if(list == null || list.isEmpty()){
                        //2.1 获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //2.1.1 解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //2.2 获取成功，下单
                    handleVoucherOrder(voucherOrder);
                    //3.ACK确认（说明队列消息已处理） SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1",record.getId());
                } catch (Exception e) {
                    log.error("订单处理异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true){
                try {
                    //1.获取pending-list中的订单信息 XREAD GROUP g1 c1 COUNT 1 STREAMS stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );

                    //2.判断消息获取是否成功
                    if(list == null || list.isEmpty()){
                        //2.1 获取失败，说明pending-list没有异常消息，结束循环
                        break;
                    }
                    //2.1.1 解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //2.2 获取成功，下单
                    handleVoucherOrder(voucherOrder);
                    //3.ACK确认（说明队列消息已处理） SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    //短暂休眠
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException e1) {
                        e1.printStackTrace();
                    }
                }
            }
        }
    }

    /*//阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
    //线程任务
    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("订单处理异常", e);
                }
            }
        }
    }*/

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户id
        Long userId = voucherOrder.getUserId();
        //2.创建分布式锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //3.获取锁
        boolean isLock = lock.tryLock();
        //4.判断是否获取锁成功
        if (!isLock){
            //获取锁失败，返回错误或者重试
            log.error("不允许重复下单");
            return;
        }
        try{
            //获取代理对象（事务）
            proxy.createVoucherOrder(voucherOrder);
        }finally {
            //释放锁
            lock.unlock();
        }
    }
    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //获取订单id
        Long orderId = redisIdWorker.nextId("order");
        //1. 执行lua脚本
        Long result = (Long) stringRedisTemplate.execute(SECKILL_SCRIPT, Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId));
        //2.判断结果是否为0
        int r = result.intValue();
        if (r != 0){
            //2.1， 不为0表示没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3.获取代理对象
        proxy = (IVoucherOrderService)AopContext.currentProxy();
        //4.返回订单id
        return Result.ok(orderId);
    }
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户id
//        Long userId = UserHolder.getUser().getId();
//        //1. 执行lua脚本
//        Long result = (Long) stringRedisTemplate.execute(SECKILL_SCRIPT, Collections.emptyList(),
//                voucherId.toString(), userId.toString());
//        //2.判断结果是否为0
//        int r = result.intValue();
//        if (r != 0){
//            //2.1， 不为0表示没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //2.2. 为0，有购买资格，将下单信息保存到消息队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //2.3.订单id
//        Long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //2.4.用户id
//        voucherOrder.setUserId(userId);
//        //2.5.优惠券id
//        voucherOrder.setVoucherId(voucherId);
//        //2.6.放入阻塞队列
//        orderTasks.add(voucherOrder);
//        //3.获取代理对象
//        proxy = (IVoucherOrderService)AopContext.currentProxy();
//        //4.返回订单id
//        return Result.ok(orderId);
//
//
//        /*//1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        //3.判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1){
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        //创建分布式锁
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        boolean isLock = lock.tryLock();
//        if (!isLock){
//            //获取锁失败，返回错误或者重试
//            return Result.fail("不允许重复下单");
//        }
//        try{
//            //synchronized(userId.toString().intern()){
//            //获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService)AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//            //}
//        }finally {
//            //释放锁
//            lock.unlock();
//        }*/
//    }
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单逻辑
        //Long userId = UserHolder.getUser().getId();
        Long userId = voucherOrder.getUserId();
        // 5.1.查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        // 5.2判断是否存在
        if (count > 0) {
            //用户已经购买过了
            log.error("用户已经购买过一次了");
            return;
        }
        // 6.扣减库存
        //boolean success = seckillVoucherService.update()
        //        .setSql("stock= stock -1") //set stock = stock -1
        //        .eq("voucher_id", voucherId).eq("stock",voucher.getStock()).update(); //where id = ？ and stock = ?
        boolean success = seckillVoucherService.update()
                .setSql("stock= stock -1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0).update(); //where id = ? and stock > 0
        if (!success) {
            //扣减库存
            log.error("库存不足！");
            return;
        }
//        // 7.创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 7.1.订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        // 7.2.用户id
//        Long id = UserHolder.getUser().getId();
//        voucherOrder.setUserId(id);
//        //7.3.代金券id
//        voucherOrder.setVoucherId(voucherId);
        // 8.保存订单
        save(voucherOrder);
//        return Result.ok(orderId);
    }
}
